/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the  "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id$
 */
package wx.xml.xalan.xalan.templates;

import wx.xml.xalan.xml.utils.FastStringBuffer;
import wx.xml.xalan.xpath.XPath;
import wx.xml.xalan.xpath.XPathContext;
import wx.xml.xalan.xpath.XPathFactory;
import wx.xml.xalan.xpath.compiler.XPathParser;
import wx.xml.xalan.xpath.objects.XObject;

/**
 * Simple string part of a complex AVT.
 *
 * @xsl.usage internal
 */
public class AVTPartXPath extends AVTPart {
    static final long serialVersionUID = -4460373807550527675L;

    /**
     * The XPath object contained in this part.
     *
     * @serial
     */
    private XPath m_xpath;

    /**
     * Construct a simple AVT part.
     *
     * @param xpath Xpath section of AVT
     */
    public AVTPartXPath(XPath xpath) {
        m_xpath = xpath;
    }

    /**
     * Construct a simple AVT part.
     *
     * @param val            A pure string section of an AVT.
     * @param nsNode         An object which can be used to determine the
     *                       Namespace Name (URI) for any Namespace prefix used in the XPath.
     *                       Usually this is based on the context where the XPath was specified,
     *                       such as a node within a Stylesheet.
     * @param xpathProcessor XPath parser
     * @param factory        XPath factory
     * @param liaison        An XPathContext object, providing infomation specific
     *                       to this invocation and this thread. Maintains SAX output state,
     *                       variables, error handler and so on, so the transformation/XPath
     *                       object itself can be simultaneously invoked from multiple threads.
     * @throws javax.xml.transform.TransformerException TODO: Fix or remove this unused c'tor.
     */
    public AVTPartXPath(
        String val, wx.xml.xalan.xml.utils.PrefixResolver nsNode,
        XPathParser xpathProcessor, XPathFactory factory,
        XPathContext liaison)
        throws javax.xml.transform.TransformerException {
        m_xpath = new XPath(val, null, nsNode, XPath.SELECT, liaison.getErrorListener());
    }

    /**
     * This function is used to fixup variables from QNames to stack frame
     * indexes at stylesheet build time.
     *
     * @param vars List of QNames that correspond to variables.  This list
     *             should be searched backwards for the first qualified name that
     *             corresponds to the variable reference qname.  The position of the
     *             QName in the vector from the start of the vector will be its position
     *             in the stack frame (but variables above the globalsTop value will need
     *             to be offset to the current stack frame).
     */
    public void fixupVariables(java.util.Vector vars, int globalsSize) {
        m_xpath.fixupVariables(vars, globalsSize);
    }

    /**
     * Tell if this expression or it's subexpressions can traverse outside
     * the current subtree.
     *
     * @return true if traversal outside the context node's subtree can occur.
     */
    public boolean canTraverseOutsideSubtree() {
        return m_xpath.getExpression().canTraverseOutsideSubtree();
    }

    /**
     * Get the AVT part as the original string.
     *
     * @return the AVT part as the original string.
     */
    public String getSimpleString() {
        return "{" + m_xpath.getPatternString() + "}";
    }

    /**
     * Write the value into the buffer.
     *
     * @param xctxt   An XPathContext object, providing infomation specific
     *                to this invocation and this thread. Maintains SAX state, variables,
     *                error handler and  so on, so the transformation/XPath object itself
     *                can be simultaneously invoked from multiple threads.
     * @param buf     Buffer to write into.
     * @param context The current source tree context.
     * @param nsNode  The current namespace context (stylesheet tree context).
     * @throws javax.xml.transform.TransformerException
     */
    public void evaluate(
        XPathContext xctxt, FastStringBuffer buf, int context, wx.xml.xalan.xml.utils.PrefixResolver nsNode)
        throws javax.xml.transform.TransformerException {

        XObject xobj = m_xpath.execute(xctxt, context, nsNode);

        if (null != xobj) {
            xobj.appendToFsb(buf);
        }
    }

    /**
     * @see XSLTVisitable#callVisitors(XSLTVisitor)
     */
    public void callVisitors(XSLTVisitor visitor) {
        m_xpath.getExpression().callVisitors(m_xpath, visitor);
    }
}
